package com.adee.java.map;

import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.concurrent.CopyOnWriteArrayList;

public class Test01_LinkedHashMap {
    public static void main(String[] args) {
        Iterator it;
        List list = new ArrayList();
        new LinkedList<>();
        new Vector<>();
        new CopyOnWriteArrayList<>();
        Map<String, String> map = new HashMap<>();
        map.put(null, "hello");
        TreeMap<String, String> tm = new TreeMap<>();
        tm.put(null, "a");
        new ConcurrentHashMap<>();
        new ConcurrentSkipListMap();
    }
}
